INTRODUCTION

Following 7 December, 1941, it was found that task forces engaged in operations ran low on fuel appreciably earlier than expected. The necessity for moving an ever increasing number of fast tankers into position for refueling slowed down and restricted offensive operations. In the early phases of the war when the number of fast tankers was limited, one task force commander described his refueling problem as the "Battle of the Fuel Oil." Two conditions became apparent:

1. There was insufficient information on wartime radius and endurance for the planning of task force operations.

2. When war service data were analyzed it was found that the actual radius of all ships was appreciably less than originally expected, and in the case of destroyers and some cruisers it was inadequate.

The above conditions resulted mainly from the practice of basing computations of cruising radius and endurance on fuel allowances for engineering scores. These allowances were established for peacetime operating conditions, under which rigid fuel economies were practiced by individual ships to obtain high scores, and fleet and force operations were planned to permit the most economical hook-ups in order to conserve fuel. In time of war task force speeds and other operations are dictated by the strategical and tactical situation, and individual ships must maintain maximum safety and readiness to meet sudden heavy demands while operating under relatively unfavorable conditions. Single or reduced boiler operation, cruising turbines and other fuel-saving arrangements can rarely be utilized. Increased displacements brought about by additional weapons, larger crews, etc., and other factors further add to wartime fuel expenditures.

In order to provide logistics data suitable for wartime use, a comprehensive study of wartime
operation was undertaken, using modern statistical methods to correlate the large mass of information available. It was found that the most fundamental relation involved in underway fuel consumption is the relation between propeller speed and hourly fuel rate. This relation was therefore made the basis for all computations. Mean hourly and daily fuel rates at various propeller speeds were determined from thousands of hours of steady run data. Endurances in hours and days were found by dividing the mean fuel rates into the fuel capacity of the ship. Common usage requires, however, that endurance in time be translated into radius in miles; this was done by multiplying endurance in hours by the estimated speed in knots. In addition to values of radius found for the mean displacement of the data period, values of radius were calculated for a lighter displacement, chosen arbitrarily. Linear interpolation of the data provides an estimate of radius at any mean displacement desired.

It has been customary in the past to express cruising radius in miles without qualification or limitation. When radius is interpreted as navigational miles, some misunderstanding may result with respect to what a ship can do. This is because the computation of radius depends in part on the R.P.M.-knot relation, which is unpredictably influenced by weather and sea conditions. It appears preferable to specify radius in engine miles. This term is used throughout the following pages. An individual ship can determine her radius in navigational miles by multiplying the endurance at a given propeller speed by the corresponding ship speed found by navigational means.

It is evident from practical considerations that no single exact value can be found for fuel rate, endurance or radius at a given propeller speed. Mean values can, however, be obtained which are representative for average conditions. In all cases it is possible to increase the significance of the mean values by supplying them with tolerances to take account of normal variations in operating conditions. The determination of these tolerances is one of the most important and valuable features of this study.

The statistical and engineering procedures employed in the analysis of war service fuel consumption data are elsewhere discussed in detail.* The results obtained are presented in FTP 218 in the form of tables and charts. The main tables provide steady steaming data for use by the Forces Afloat in planning war operations and for consideration by those concerned with future design. The data are also presented graphically in charts from which relations between speed, fuel consumption, and days and miles steamed can be picked off quickly and conveniently. The charts are subdivided to show what can be done with any given amount of oil in excess of 20 per cent held in reserve and what can be done with the last 20 per cent of fuel on board. Additional tables provide average underway data, not-underway data, and other pertinent information. The data have been published in loose-leaf form to facilitate inclusion of revisions and additions.

FTP 218, containing data on war service fuel consumption, will be supplemented by a second publication containing fuel allowances for peacetime operations, based on a statistical analysis of data collected and analyzed when the Fleet is operating under a peacetime organization. THE FUEL ALLOWANCES FOR PEACETIME OPERATIONS WILL NEVER BE USED TO COMPUTE ENDURANCE OR RADIUS OR TO PROVIDE A BASIS FOR DESIGN.

* Bureau of Ships Research Memorandum No.3-44 (War Service Fuel Consumption:
Theory and Construction of Underway Tables and Charts).

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DISCUSSION OF TABLES AND CHARTS

1. The following articles contain a general discussion of the practical factors which were taken into account in preparing the tables and charts on war service fuel consumption, together with information regarding their use and meaning. A description of the statistical methods and theories employed in processing the service data will be published separately as Bureau of Ships Research Memorandum No.3-44, entitled "War Service Fuel Consumption: Theory and Construction of Underway Tables and Charts."

Table I. WAR LOGISTICS DATA FOR STEADY STEAMING

2. Table I and its supplement§ contain the main portion of useful information on wartime fuel consumption found by statistical analysis of service data. The raw data were obtained directly from Daily Work Sheets or Underway Data Sheets and Monthly Summaries. The mean displacement for the fuel data period was obtained by averaging draft readings. Fuel capacities and R.P.M.-knot relations were provided by the Navy Department. The R.P.M.-knot relations were estimated from trial data or from model basin tests; trial data were used wherever available. The steady steaming data as shown in table I cover all normal operating variables, including fouling. In view of the varied service experience with plastic paint no adjustment of the data for time out of dock is used. A detailed description of table I (sample on facing page) is given below.

3. Column (1).--The propeller speeds listed in column (1) are a guide for the entire table. While the use of knots in this column would appear preferable, it was not possible for the following reason: The R.P.M.-hourly fuel rate relation

can be determined accurately from service data by statistical means; the knot-hourly fuel rate relation cannot be so determined because there is no accurate method for making routine measurements of the true ship speed in knots. Data at propeller speeds corresponding to whole-number values of estimated ship speed (11 knots, 12 knots, etc.) have been obtained by interpolation and are inserted for convenience in columns of the table most frequently used. In the case of certain ships, destroyers for example, the interpolated values are given separately in table IAA.

4. Columns (2)-(11).--The information given in table I for various values of R.P.M. is of three main types:

a. Columns (2)-(6).--The fuel rates and endurances provided in these columns are actual values found for the fundamental relation between propeller speed and service fuel rate. These values were determined accurately from large quantities of service data observed at displacements varying about the indicated mean service displacement. Throughout this study endurance is expressed on a time basis of hours and days and is distinguished from cruising radius in miles. The endurances as given are independent of external factors which affect speed through the water or over the ground.

b. Columns (9)-(11).--Cruising radii in engine miles and engine-mile fuel rates are given in column (10) and column (11) for mean service displacement. These radii and fuel rates are derived values, obtained by combining the fundamental fuel consumption data in columns (2)-(6) with the estimated R.P.M.-knot relation in column (9).

c. Columns (7) and (8).--Column (8) gives cruising radius in engine miles at an arbitrary mean displacement which is lighter than the mean
service displacement. These radii are calculated values which correspond to the R.P.M.-knot relation estimated for the assumed lighter displacement and given in column (7).

5. Fuel rate and endurance.--The values of fuel rate and endurance given in columns (2)-(6) are representative of war service operations when the steady speeds maintained are constant within 0.5 knot. Greater variations in speed give higher fuel rates and lower endurances. The values as given cover all normal variations in fuel consumption related to such changeable conditions as fouling, weather, material maintenance, operational readiness of machinery, and proficiency of personnel. They do not cover abnormal conditions such as underwater damage, one or more engines out of commission, or excessive fouling of hull and propellers. If the ship is operating on less than the full number of engines with propellers removed from idle shafts and other conditions approximately normal, the relation between knots and fuel rate is not greatly changed; table I or its supplement§ may be used under these conditions with fair accuracy by referring to the ship speeds given instead of propeller speeds.

6. Ship speed and radius.--While fuel rates and endurances can be determined accurately by analysis of service data, the R.P.M.-knot relation for service conditions can only be estimated. The actual ship speed made for a fixed propeller speed varies considerably with wind, sea, condition of bottom, etc., and there is no practicable method now available by which to measure or evaluate this variation. Accordingly, it was necessary to estimate mean ship speeds for various propeller speeds from R.P.M.-knot relations at clean-bottom trial conditions. This was done by adjusting the trial or model basin data to include an

§ Table IA or IAA.

--2--

Sample table

CL 49

Table I.--WAR LOGISTICS DATA FOR STEADY STEAMING

DATA PERIOD: 1942-1943

BASED ON RADIUS OIL*

Ships in Class:CL 49

PROP. SPEED

(1)

FUEL RATE

ENDURANCE

SPEED

RADIUS

SPEED

RADIUS

FUEL RATE

WORK COLUMN

MEAN

NORMAL RANGE

DAILY

Mean displacement 13,500 tons†

Mean displacement 11,500 tons

Mean displacement 13,500 tons †

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

R.P.M.

Gal./hr.

Gal./hr.

Bbl./day

Hours

Days

Knots

Engine miles

Knots

Engine miles

Gal./eng. mi.

100

634

519-764

362±26

898±15

37.4

10.4±0 1

10,140±270

10.3±0.1

9,250±250

61.6

11.0

9,080

62.7

110

714

584-861

408±29

797±14

33.2

11.4±.1

10,110±270

11.3±.1

9,010±240

63.2

12.0

8,800

64.7

120

804

658-969

459±33

708±13

29 5

12.4±.1

9,760±260

12.3±.1

8,710±240

65.4

13.0

8,460

67.3

130

906

741-1,092

518±37

628±12

26 2

13.4±.1

9,490±250

13.3±.1

8,350±230

68.1

14.0

8,090

70.3

140

1,020

835-1,229

583±42

558±12

23 2

14.5±.1

9,110±250

14.3±.1

7,980±230

71.3

15.0

7,690

74.0

160

1,149

940-1,385

657±47

495±11

20.6

15.5±.1

8,650±250

15.3±.1

7,570±220

75.1

16.0

7,290

78.1

160

1,294

1,059-1,560

739±53

440±10

18 3

16.5±.1

8,280±240

16.3±.1

7,170±220

79.4

17.0

6,880

82.8

170

1,457

1,192-1,756

833±60

391±10

16 3

17.5±.1

7,880±240

17.3±.1

6,760±220

84.2

18.0

6,470

88.0

180

1,641

1,343-1,978

938±68

347±9

14 5

18.5±.1

7,490±240

18.3±.1

6,350±210

89.7

19.0

6,010

94.8

190

1,848

1,512-2,227

1,056±76

308±9

12 8

19.4±.1

7,060±240

19.2±.1

5,910±210

96.2

20.0

5,590

101.7

200

2,082

1,704-2,509

1,190±86

273±8

11 4

20.4±.1

6,670±240

20.2±.1

5,510±210

103.1

21.0

5,170

110 2

210

2,344

1,918-2,825

1,339±97

243±8

10.1

21.3±.1

6,260±240

21.1±.1

5,130±210

111.1

220

2,640

2,160-3,182

1,509±109

216±7

9 0

22.3±.2

5,820±240

22.0±.2

4,750±210

120 0

230

2,973

2,433-3,583

1,699±122

191±7

8 0

23.2±.2

5,430±240

22.9±.2

4,370±210

129 8

170 i 7

23.0

4,330

131 0

240

3,349

2,741- 4,036

1,914±138

7 1

24.1±.2

5,010±220

23.8±.2

4,050±210

140.7

24.0

3,990

143.0

250

3,771

3,086-4,545

2,155±155

151±6

6.3

25.1±.2

4,690±220

24.8±.2

3,740±190

152.0

25.0

3,680

154.5

260

4,247

3,475-5,118

2,427±175

134±6

5.6

26.2±.2

4,350±220

25.8±.2

3,460±190

164.6

26.0

3,410

167.4

270

4,783

3,914-5,764

2,733±197

119±6

5.0

27.2±.2

4,050±220

26.8±.2

3,190±190

178.5

27.0

3,140

175.4

280

5,387

4,408-6,492

3,078±222

106±5

4.4

28.2±.3

3,720±220

27.8±.3

2,950±180

193.8

28.0

2,870

199.3

290

6,067

4,965-7,312

3,467±250

94±5

3 9

29.0±.3

3,420±220

28.5±.3

2,680±180

212.9

29.0

2,520

225.6

300

6,833

5,592-8,235

3,905±281

83±5

3 5

29.8±3

3,100±190

29.3±.3

2,430±180

233.2

310

7,695

6,297-9,274

4,397±317

74±5

3 1

30.5±.3

2,810±190

30.0±.3

2,220±180

256.5

320

8,666

7,092-10,444

4,952±357

66±4

2 8

31.2±.3

2,500±190

30.7±.3

2,030±150

282.3

31.0

1,920

297.0

330

9,760

7,987-11,763

6,577±402

58±4

2.4

31.8±.3

2,260±150

31.3±.3

1,820±150

311.8

339

10,862

8,889-13,091

6,207±447

52±4

2.2

32.3±.3

2,070±150

‡31.8±.3

1,650±150

341.6

* See table V.

† Mean displacement during data period.

‡ Estimated speed at designed shaft horsepower (100,000 s.h.p.).

--3--

arbitrary increase in shaft horsepower of 12.5 percent, thus making some allowance for the mean effect of weather, fouling, etc. The tolerances on speed were similarly estimated. Since the determination of radius depends in part on this estimated R.P.M.-knot relation, values of radius are to this extent approximate. This is in contrast to the fundamental accuracy of the endurances used in determining the radii.

7. Displacement.--The radii in column (10), as well as all fuel rates and endurances in other columns of the table, were obtained at actual displacements which varied about the indicated mean service displacement. For operations in which displacement varies about a different mean displacement these values are not expected to hold. The purpose of columns (7) and (8) is to indicate the effect of displacement on speed and radius and to provide a means of estimating radius for a different mean displacement by simple linear interpolation. The mean displacement specified for these two columns was chosen arbitrarily and does not represent any actual operating condition.

8. Fuel capacity.--All endurances and radii in table I are based on the fuel capacity defined as radius oil in table V. For some ships, particularly destroyers, radius oil and maximum capacity (95%) are identical. Where they are not identical the supplementary table IA has been prepared to show endurance and radius based on maximum capacity (95%). Further remarks concerning the two fuel capacities will be found below in article 19.

9. Ship classes.--Table I gives data for a class of ships wherever such a grouping was possible on the basis of similarity of hull, propellers, and engineering plant. The purpose of this grouping was to supply planners with over-all information and to make it possible for individual ships to compare their own performance with the mean performance of their class. The values shown for a class are means of the mean values obtained for each ship of the class or for those ships used to represent the class. The fuel rates, endurances, and radii of any ship in a class are indicated with reasonable accuracy by the mean class values. More precise values can be found by taking into account the mean fuel rate of the individual ship. The information required to make these adjustments is provided in table VI; the method of adjustment is described below in articles 20 and 21.

The ships constituting each class are indicated on the chart and tables given for the class concerned. Since the grouping of ships by classes in the study of fuel consumption was made in accordance with machinery, hull and propeller similarities, as noted above, the classes designated are not identical with classifications in current use in the Fleet.

10. Tolerances.--Since the tolerances as supplied with mean values of fuel rate, endurance, etc., are an innovation in the study of the fuel consumption of naval vessels, the following explanation is given to illustrate their use and meaning. The tolerances do not represent variations in the means themselves; rather, they indicate the limits within which individual observed values may normally be expected to fall. In column (2), for example, a given hourly fuel rate is the arithmetic mean of individual service fuel rates at the indicated propeller speed. The normal range of variation among these individual rates is indicated by the upper and lower limits given in column (3). In tables for single ships, a "normal range" found in column (3) should contain about 90 percent of the individual fuel rates observed when the ship concerned operates under service conditions at the given propeller speed; about 5 percent of the observed rates will probably exceed the upper limit and about 5 percent will probably fall below the lower limit. In column (4) of tables for single ships the tolerances on daily fuel rates should include more than 99 percent of observed individual daily fuel consumptions. In tables for classes of ships, the tolerances on the hourly fuel rate will include about 90 percent of the individual hourly rates observed and the tolerances on daily fuel rate will include about 99 percent of the individual daily rates observed after the class data have been adjusted to the particular ship concerned. As previously noted, these adjustments are made by use of table VI.

Tolerances on fuel rate and endurance were derived directly from the statistical distribution of the service data. In determining the tolerances on daily fuel rate it was assumed that large hourly variations tend to cancel over extended periods of steady steaming. Tolerances on radius are a composite of endurance tolerances and the estimated tolerances on speed.

11. Interpolations.--Linear interpolations may be made in all columns of table I and its supplement§ to obtain data for speeds other than those shown. In addition, radius and ship speed may be adjusted to mean displacements other than the two for which data are given. The accuracy of linear interpolation is well within the accuracy of the tables. Data at propeller speeds corresponding to whole-number knots (11 knots, 12 knots, etc.) have been calculated and are included in the tables. Values of radius are adjusted to a desired mean displacement by interpolation between the values found in table I in columns (8) and (10). Ship speeds are similarly adjusted for displacement by interpolation between the speeds in columns (7) and (9); at low speeds, however, this adjustment tends to be negligible.

§ Table IA of IAA.

--4--

12. Other derivations.--In addition to interpolations at desired speeds and mean displacements, a variety of other calculations may be carried out to adjust the data in table I and its supplement§ for specific purposes. Several illustrations are given below. Tolerances as well as mean values may be adjusted; when a mean fuel rate, mean endurance, or mean radius is multiplied by some factor, the corresponding tolerance is multiplied by the square root of that factor.

a. Fuel consumption for several days of steaming.

Example:

Find the quantity of fuel consumed by CL 49 in 4 days of steady steaming at 200 R.P.M.

Solution.

Bbl./day × 4 days = 1190 × 4± 86√4 = 4760 ± 172 bbl.

b. Endurance and radius for a partial load of fuel.

Example:

Find the endurance and radius that CL 49 will have at 200 R.P.M. if she fuels to radius oil capacity and holds 25% of her fuel in reserve.

13. It will be noted by reference to table V that two fuel capacities are given for each ship or class: (1) Radius oil, which is an optimum capacity based on damage control considerations, and (2) maximum capacity (95%). For some ships the two capacities are identical. For others, the radius oil is less than the maximum capacity (95%). In table I endurance and radius are based on radius oil. Tables IA and IAA (samples on facing page) provide simplified steady steaming data and are supplementary to table I; values for endurance and radius in tables IA and IAA are based on maximum capacity (95%). Only one or the other of the supplementary tables is given for each ship or class.

14. Table IA.--In the case of ships whose maximum capacity (95%) is materially greater than the designated radius oil, table I is supplemented by table IA. The supplementary table contains values of endurance and radius based on maximum capacity (95%) to show what can be done if all available fuel tanks are filled. These values together with corresponding fuel rates are given for estimated ship speeds in whole-number knots. The increased endurances and radii shown in table IA are obtained at the expense of reserve buoyancy and resistance to underwater damage.

15. Table IAA.--For those ships whose radius oil and maximum capacity (95%) are identical (destroyers, for example) table I is supplemented
by table IAA. The latter table contains values of endurance, radius, and fuel rate found by interpolation for ship speeds in whole-number knots.

Table II. WAR LOGISTICS DATA: UNDERWAY AVERAGES

16. Table II shows the average propeller speed for all underway operations and the resulting average fuel consumption of the ships concerned (sample on facing page). These values include both steady steaming data and data recorded when propeller speeds were changing. The calculation of endurance was based on radius oil capacity, given in table V. When basic fleet speeds correspond roughly to the indicated average propeller speed, table II may be used as the basis of preliminary long range estimates of fuel requirements. By totaling such estimates for ships in an area the number of tankers or other fuel storage units required in that area can be determined.

Table I and table II are based on the same data period. If the over-all average fuel rate in table II is compared with the corresponding steady steaming fuel rate, found from table I by interpolation at the over-all average propeller speed, it will be noted that the over-all rate is higher. This is to be expected since fuel rates tend to be higher when speed is changing than when speed is practically constant.

Table III. WAR LOGISTICS DATA: NOT UNDERWAY

17. The values given in table III (sample on facing page) are averages of all not-underway data reported with the underway data on which table 1 and table II are based. The calculation of endurance was based on radius oil capacity, given in table V. Not-underway fuel rates vary widely under war conditions, depending on the state of security of the anchorages, etc., but at all times are much greater than peacetime port rates.

Table IV. PROPELLER SPECIFICATIONS

18. The specifications given in table IV (sample on facing page) pertain to the propellers actually in use during the period for which the underway fuel consumption data in table I and table II were obtained. Since any material changes in propeller characteristics affect both fuel rates and R.P.M.-knot relations, the data given in tables I and II are accurate only if the propellers installed are those specified. Some use of tables I and II may be made, however, even if the propellers have been changed and differ from the specifications in table IV. In such cases, if the first column (average propeller speed) of tables I and II are deleted, the remaining data are sufficiently accurate for most logistics purposes. Under these circumstances the ship speed columns are to be used as a guide in place of the propeller speed columns.

When major propeller changes are made it is intended that new fuel consumption data will be collected and analyzed with subsequent revision of the charts and tables.

[Note: Fueling beyond the radius oil capacity increases radius at the expense of resistance to underwater damage. This table is made available to the commander as a supplement to table I for use when increased radius and decreased resistance to underwater damage are factors in a decision.]

Speed

Radius

Endurance |

Fuel rate

Mean displacement 13,500 tons

Knots

Engine miles

Days

Bbl./day

11

10,190

38.7

394

13

9,880

34.4

444

13

9,500

30.5

500

14

9,080

27.1

564

15

8,630

24.0

635

16

8,180

21.3

714

17

7,720

19.0

805

18

7,260

16.8

906

19

6,750

14.8

1,030

20

6,280

13.1

1,163

21

5,800

11.5

1,322

22

5,330

10.1

1,509

23

4,860

8.9

1,723

24

4,480

7.7

1,962

25

4,130

7.0

2,209

26

3,830

6.2

2,488

27

3,520

5.5

2,802

28

3,220

4 8

3,189

29

2,830

4.0

3,741

30

2,490

3.5

4,397

31

2,160

2 9

5,264

* See table V.

DD 409 CLASS

Table IAA--WAR LOGISTICS DATA FOR STEADY STEAMING

BASED ON MAXIMUM CAPACITY (95%)*Data For Integral Ship Speeds

Speed

Radius

Endurance

Fuel rate

Mean displacement 2,350 tons

Knots

Engine miles

Days

Bbl./day

12

5,640

19.7

167

13

5,480

17.6

186

14

5,260

15.6

208

15

5,010

13.9

234

16

4,770

12.4

263

17

4,490

11.0

296

18

4,220

9 8

334

19

3,940

8.7

377

20

3,660

7.6

428

21

3,380

6.7

486

22

3,110

5.9

553

23

2,850

5.2

633

24

2,560

4.5

732

25

2,260

3.8

869

26

2,000

3 2

1,022

27

1,760

2.7

1,206

28

1,550

2.3

1,405

29

1,390

2.0

1,636

30

1,240

1.8

1,903

31

1,100

1 5

2,184

32

1,010

1.3

2,468

33

920

1.2

2,820

34

860

1.0

3,151

* See table V.

CL 49

Table II.--WAR LOGISTICS DATA: UNDERWAY AVERAGES

Average speed

Fuel rate

Endurance*

R.P.M.

Knots

Bbl./day

Days

162.9

16.6

852±229

15 9±1.5

* Based on radius oil; see table V.

CL 49

Table III.--WAR LOGISTICS DATA: NOT UNDERWAY

Fuel rate

Endurance*

Gal./hr.

Bbl./day

Days

202

115

117.4

* Based on radius oil; see table V.

CL 49

Table IV.--PROPELLER SPECIFICATIONS

[Note: All underway data are based on the propellers specified below. In case of a propeller change see discussion of table IV in Introduction.]

Number of propellers

Number of blades

Diameter

Pitch

2 inbound

3

11'95/8"

11'65/8"

2 outboard

3

11'95/8"

11'97/8"

--7--

Table V. FUEL CAPACITIES

19. Two fuel capacities are given in table V: (1) Radius oil and (2) maximum capacity (95%). The need for establishing the radius oil capacity arose from the fact that fueling certain ships to maximum capacity appreciably reduces reserve buoyancy and resistance to underwater damage. The radius oil capacity represents the best obtainable compromise between cruising radius and damage control requirements. Both radius oil and maximum capacity (95%) are given for each ship or class. Values for endurance and radius in tables I, II and III are based on radius oil. An additional table, table IA, is provided to show steady steaming endurance and radius based on maximum capacity (95%), if this capacity is materially greater than radius oil. It will be noted that for some ships, destroyers in particular, radius oil and maximum capacity (95%) are identical.

The fuel capacities in table V (samples in center column) are expressed in tons, barrels, and gallons. The conversion factors used to change tons to gallons and gallons to barrels are given at the bottom of the table. For uniformity the capacities have been based throughout on 95 percent of tank capacity. The actual amount of fuel which is available, however, depends on a large number of factors, among which are the following: Viscosity, expansion or contraction with change in temperature, shape of tanks, immediate ballasting or repumping after settling, piping arrangements, and the amount of fuel initially pumped into the tanks.

Table VI. STEADY STEAMING MEAN FUEL RATE RATIOS

20. Table VI has been prepared for the purpose of enabling any ship of a class to obtain an accurate picture of her own performance by adjustment
of the data in table I and its supplement§ which show the mean performance of her class. The latter tables generally represent all ships which can be considered the same from the point of view of similarity of hull, engineering plant, etc.; they represent an individual ship if that ship is the only vessel of the class. It has been found, however, that ships in the same class may show marked differences in performance which cannot be completely explained, although differences in displacement and engineering practices account for some of them. Table VI (sample on facing page) shows these performance differences quantitatively by means of fuel rate ratios, which were determined accurately by analyzing service data and comparing the mean fuel rates of the individual ships with the mean fuel rates of the class. The example in article 21 shows how table VI is used to adjust table I to a particular ship.

Some ships are not included in the ratio table provided for their class because of lack of data for these ships when the table was prepared. The ships omitted will be included in later editions. In the interim they may derive their ratios by comparing their own data with the mean class data.

By interpolation in table VI for the DD 409 Class, the mean fuel rate ratio of the U.S.S. Russell is found to be 95 percent (or 0.95) at 260 R.P.M. and 2,400 tons mean displacement. By

§ Table IA or IAA.

Sample tables

CL 49
Table V.--FUEL CAPACITIES

Capacity

Gallons Barrels

Tons

"Full load" fuel oil capacity§

524,084

12,478

1,892

Diesel oil capacity (95%)

45, 216

1,077

144

Total: radius oil*.

569,300

13,555

2,036

Additional fuel oil required to fill all tanks to 95% (emergency)

69,804

1,662

252

Total: maximum capacity (95%)†

639,104

15,217

2,288

§ Based on considerations of cruising radius and power of survival as affected by reserve buoyancy.
* In tables I, II, and III endurance and radius are based on radius oil.
† In table IA endurance and radius are based on maximum capacity (95%).

Conversion factors:

Diesel oil:

314 gallons=1 ton.

Fuel oil:

277 gallons=l ton.

Diesel oil and fuel oil:

42 gallons = 1 barrel.

DD 409 CLASS
Table V.--FUEL CAPACITIES

Capacity

Gallons

Barrels

Tons

"Full load"§

125,481

2,988

453

Diesel oil capacity (95%)†

11,304

269

36

Total: radius oil*.

136,785

3,257

489

Additional fuel oil required to fill all tanks to 95% (emergency)

0

0

0

Total: maximum capacity (95%)*.

136,785

3,257

489

§ Based on considerations of cruising radius and power of survival as affected by reserve buoyancy.

† When the Diesel tank authorized for diol stowage is utilized for that purpose, total Diesel oil capacity (95%) will be less than the values shown above; accordingly, endurance and radius will be somewhat less than values given in tables I--III.

* For this class of vessels radius oil and maximum capacity (95%) are identical.

Conversion factors:

Diesel oil:

314 gallons = 1 ton.

Fuel oil:

277 gallons = 1 ton.

Diesel oil and fuel oil:

42 gallons = 1 barrel.

--8--

means of this ratio the data given in table I for 260 R.P.M. are adjusted as follows:

Column

Adjusted Values for DD 414

(2)

0.95 × 1,869

= 1,776 gal./hr.

(3)

0.95 × 1,595

= 1,515 gal./hr.

0.95 × 2,171

= 2,062 gal./hr.

(4)

0.95 × (1,068±61)

= 1,015±58 bbl./day.

(5)

(73±4) ÷ 0.95

= 77±4 hours.

(6)

3.0 ÷ 0.95

= 3.2 days.

(10)

(1,920±130) ÷ 0.95

= 2,020±140 eng. mi.

(11)

0.95 × 71.1

= 67.5 gal./eng. mi.

Sample table

DD 409 Class
Table VI.--STEADY STEAMING MEAN FUEL BATE RATIOS*

Ship

Average displacement

Fuel rate ratio--Ship: Class

100 R.P.M.

150 R.P.M.

200 R.P.M.

250 R.P.M.

300 R.P.M.

350 R.P.M.

Tons

Percent

Percent

Percent

Percent

Percent

Percent

U.S.S. Hughes

DD 410

2,350

111.0

108.0

105.1

102.3

99.4

96.6

U.S.S. Anderson

DD 411

2,350

96.4

98.5

100.7

102.8

104.9

107.1

U.S.S. Mustin

DD 413

2,350

93.5

95.6

97.6

99.6

101.7

103.7

U.S.S. Russell

DD 414

2,400

99.1

97.8

96.6

95.3

93.9

92.6

* Table VI is used to adjust the class data in tables I and IAA to individual ships. The ratios were obtained by dividing the steady steaming mean fuel rates of the indicated ships by the corresponding mean fuel rates given in column (2) of table I.

* Same as maximum capacity (95%) for this class of vessels; see table V.
† Mean displacement during data period.
‡ Estimated speed at designed shaft horsepower (50,000 s.h.p.).

--9--

ENDURANCE AND RADIUS CHART FOR WAR STEADY STEAMING

22.The endurance and radius chart is a graphical representation of the war steady steaming data given in table I for mean service displacement. The chart was designed to give instantaneous solutions to practical problems involving days and engine miles steamed and quantity of fuel consumed at any given speed or combination of speeds. For example, for a given speed and fuel quantity the number of days or engine miles that can be steamed may be determined; or for a given speed the quantity of fuel used or quantity remaining after steaming for a given number of days or miles may be found. The chart shows also the maximum speed that can be maintained if the ship is to steam for a given number of days or miles on a given quantity of fuel.

23. Engine miles steamed.--Since a reserve of fuel is always allowed in planning operations, the chart was constructed to take this into account. Instead of showing miles steamed by one set of curves based on all fuel available, two sets of curves are given, one set based on fuel available for operations in excess of a reserve and the other set based on the reserve. The curves labeled in miles to the left of the heavy vertical "20 percent line" (see sample chart on facing page) show what can be done with fuel on board in excess of 20 percent of the full load or, in other words, what can be done if 20 percent of the full load is held in reserve for safety. These curves slope downward to the left. The curves labelled in miles to the right of the 20 percent line show what can be done with the 20 percent reserve and slope downward to the right. The number of miles that can be steamed on all fuel on board, including the reserve, is therefore the sum of two readings, one found to the left of the 20 percent line and the other found to the right of this line. For example, at point D on the sample chart the ship represented has on board 57.5 percent of her full fuel load. By inspection, she can steam 4,000 miles at 21.7 knots and still retain her 20 percent reserve. By expending the reserve she can steam an additional 2,200 miles at the same speed, or a total of 6,200 miles. On a full load of fuel she could have steamed 8,000 miles plus 2,200 miles, or a total of 10,200 miles at 21.7 knots. If values based on a different reserve such as 25 or 30 percent are desired, they may be obtained as illustrated below in article 25c.

24. Days steamed.--The curves for days of steaming slope downward to the right throughout the chart and may be used to solve problems involving the quantity of fuel remaining on board after the ship has steamed at a given speed for a given number of days or, vice versa, the number of days that can be steamed at that speed on a specific quantity of fuel. The horizontal distance between two adjacent curves shows the amount of fuel consumed in 1 day of steaming at the indicated speed. Since fuel consumption increases with increasing speed, this distance becomes greater toward the bottom of the chart. The number of days steamed can be counted either by counting spaces between curves at the desired speed or by referring to the numbers along the top of the chart, which are interpreted as follows: The number of a given curve corresponds to the number of days actually steamed provided the operation is begun on a full load of fuel; if the operation is begun on a partial load of fuel, the number of days steamed corresponds to the difference between the numbers of the two curves concerned. For example, the ship in the sample chart, if fully fueled, can steam for 42 days at 14 knots and have 20 percent of her fuel remaining. (See demonstration 1a.) If she commences steaming on only 50 percent of her full fuel load, she can steam at 14 knots for 42 minus 26 (or 16) days and have 20 percent of her fuel remaining. Values based on any desired reserve may be obtained directly from the chart without interpolation or adjustment. For example, if the ship in the sample chart maintains a 30 percent reserve, she can steam at 14 knots for 36.5 days starting with a full fuel load, and 36.5 minus 26 (or 10.5) days, starting with a 50 percent load of fuel.

25. Sample problems solved by the chart.

Note.-- In picking values from the chart a pair of dividers or a straight edge is helpful. Dividers are useful in measuring or marking off horizontal distances corresponding to fuel quantities or to the number of days or miles steamed. In place of dividers a marked slip of paper may be used or spaces between curves may be counted. A straight edge placed vertically on the chart connects fuel quantities with corresponding points on or between the curves.

a. If the ship in the sample chart took on a full load of fuel, steamed 10 days at 15 knots, 2 days at 23 knots, and then transferred a total of 150,000 gallons of fuel to two destroyers:

(1) At what speed could she steam to a point 4,000 miles away, arriving with 20 percent of her fuel remaining on board?

Solution: 21.7 knots (demonstration 3a).

(2) How long would she take to make the voyage?

Solution: 7.6 days (demonstration 3a).

(3) How many additional miles could she steam at 21.7 knots if she expended her last 20 percent of fuel?

Solution: 2,200 eng. mi. (demonstration 3b).

b. If the ship in the sample chart steamed 1,500 miles at 21.7 knots with 57.5 percent of her full fuel load initially on board, how much fuel would she require to refuel to capacity at the end of the operation?

Solution:

Gallons

Fuel capacity (radius oil)

*1,757,000

Fuel on board after operation

*765,000

Required to refuel to capacity

†992,000

c. If the ship in the sample chart increased her reserve from 20 to 30 percent, how many miles could she steam at 22 knots on a full load of fuel?

* These conversion factors are all based on the entries in the last line (tons-gallons), which assume for fuel oil a specific gravity of 0.9708 at 60°/60° F., and for Diesel oil a specific gravity of 0.8566 at 60°/60° F.

B. CONSUMPTION RATES

To convert from--

To--

Multiply by--

Barrels (petroleum) per day

Gallon (IT.8.) per hour

*1.75

Gallon (U.S.) per hour

Barrels (petroleum) per day

0.57143

* Exact.

C. WEIGHTS

To convert from--

To--

Multiply by--

Kilograms

Pounds

2.20462

Pounds

Kilograms

0.453592

Tons (long)

Kilograms

1,013.047

Tons (long)

Pounds

*2,240

Tons (long)

Tons (metric)

1.01605

Tons (metric)

Tons (short)

1.12

Tons (metric)

Kilograms

*1,000

Tons (metric)

Pounds

2,204.6223

Tons (metric)

Tons (long)

0.98421

Tons (metric)

Tons (short)

1.10231

Tons (short)

Kilograms

907.185

Tons (short)

Pounds

*2,000

Tons (short)

Tons (long)

0.892867

Tons (short)

Tons (metric)

0.907185

*Exact.

D. MEASURES

To convert from--

To-

Multiply by--

Barrels (petroleum)

Cubic feet

5.61458

Barrels (petroleum)

Gallons (U.S.)

*42

Barrels (petroleum)

Liters

158.984

Cubic feet

Barrels (petroleum)

0.17811

Cubic feet

Gallons (Imperial)

6.2288

Cubic feet_____

Gallons (U.S.)

7.4805

Cubic feet

Liters

28.316

Cubic inches

Gallons (Imperial)

0.003605

Cubic inches

Gallons (U.S.)

0.004329

Cubic inches

Liters

0.01639

Cubic meters

Gallons (Imperial)

219.97

Cubic meters

Gallons (U.S.)

264.17

Cubic meters

Liters

999.97

Gallons (Imperial)

Cubic feet

0.16054

Gallons (Imperial)

Cubic inches

277.42

Gallons (Imperial)

Cubic meters

0.0045461

Gallons (Imperial)

Gallons (U.S.)

1.20094

Gallons (Imperial)

Liters

4.54609

Gallons (U.S.)

Barrels (petroleum)

0.0238095

Gallons (U.S.)

Cubic feet

0.133681

Gallons (U.S.)

Cubic feet

*231

Gallons (U.S.)

Cubic meters

0.00378543

Gallons (U.S.)

Gallons (Imperial)

0.83268

Gallons (U.S.)

Liters

3.78533

Liters

Barrels (petroleum)

0.00628995

Liters

Cubic feet

0.035315

Liters

Cubic inches

61.025

Liters

Cubic meters

0.00100003

Liters

Gallons (Imperial)

0.219975

Liters

Gallons (U.S.)

0.264178

* Exact.

--13--

APPENDIX B
CHARACTERISTICS OF U.S. NAVAL TANKERS

VESSEL

DEADWEIGHT(Tons)

SPEED(Knots)

FUEL CAPACITY*

PUMPING CAPACITY (per pump)

FUEL OIL

DIESEL OIL

GASOLINE

TOTAL

FUEL OIL PUMPS-- MAIN CARGO

FUEL OIL PUMPS-- STRIPPER

DIESEL OIL PUMPS

GASOLINE PUMPS

Bbl.

Bbl.

Bbl.

Bbl.

Number

Gal./Min.

Number

Gal./Min.

Number

Gal./Min.

Number

Gal./Min.

AO 3 Cuyama

9,800

14.0

41,500

8,800

2,300

52,600

2

2,100

2

180

1

300

AO 4 Brazos

9,500

13.8

39,800

8,000

3,800

51,600

2

2,000

2

350

1

500

AO 11 Sapelo

12,600

10.5

61,840

9,300

6,685

77,825

2

2,000

2

420

2

200

AO 12 Ramapo

12,000

10.7

57,700

9,300

0

67,000

2

2,000

2

420

2

200

AO 13 Trinity

12,600

11.2

60,400

18,000

6,600

85,000

2

2,000

2

420

2

200

AO 15 Kaweah

10,200

11.0

45,450

8,570

8,929

62,949

2

960

2

450

2

450

AO 16 Laramie

10,200

11.2

47,300

8,570

9,929

65,799

2

960

2

450

2

450

AO 17 Mattole

10,200

11.0

57,000

520

0

57,520

2

960

2

450

2

450

AO 18 Rapidan

10,610

11 6

60,000

8,800

0

68,800

2

2,000

2

420

2

200

AO 19 Salinas

12,600

10.3

50,000

4,000

6,000

60,000

2

2,000

2

420

2

200

AO 20 Sepulga

10,610

11.8

65,000

0

0

65,000

2

2,000

2

420

2

200

AO 21 Tippecanoe

12,600

10.5

63,509

8,850

0

72,359

2

2,000

2

420

2

200

AO 22 Cimarron

18,250

19.0

87,246

9,968

19,600

116,814

3

2,000

2

1,400

1

1,400

4

250

AO 24 Platte

18,250

18.0

68,054

16,175

19,000

103,229

3

2,000

2

1,400

1

1,400

4

250

AO 25 Sabine

18,250

18 0

68,054

16,215

19,000

103,269

3

2,000

2

1,400

1

1,400

4

250

AO 26 Salamonie

18,250

18.0

76,700

16,615

23,300

116,615

3

2,000

2

1,400

1

1,400

4

250

AO 27 Kaskaskia

18,250

18 0

68,054

16,032

18,771

102,857

3

2,000

2

1,400

1

1,400

4

250

AO 30 Chemung

18,250

18.0

79,800

16,500

18,600

114,900

3

2,000

2

1,400

1

1,400

4

250

AO 32 Guadalupe

18,250

18.0

68,054

17,026

15,491

100,571

3

2,000

2

1,400

1

1,400

4

250

AO 34 Chicopee

16,450

15 5

82,400

15,300

16,100

113,800

3

2,000

2

700

1

700

4

250

AO 35 Housatonic

16,450

15.5

68,000

15,000

18,900

101,900

3

2,000

1

700

1

700

4

250

AO 36 Kennebec

15,510

16.5

70,000

16,050

16,700

102,750

3

2,000

1

700

1

700

4

250

AO 37 Merrimack

15,510

16 5

72,000

16,050

16,700

104,750

3

2,000

1

700

1

700

4

250

AO 38 Winooski

15,510

12 5

77,000

16,050

16,700

109,750

3

2,000

1

700

1

700

4

250

AO 39 Kankakee

15,510

16.5

73,500

15,000

15,000

103,500

3

2,000

1

700

1

700

4

250

AO 40 Lackawanna

15,510

16 5

80,000

8,000

14,000

102,000

3

2,000

1

700

1

700

4

250

AO 41 Mattaponi

16,000

16 5

70,000

15,400

15,000

100,400

3

2,000

1

700

1

700

4

250

AO 42 Monongahela

16,000

16.5

70,000

16,000

14,800

100,800

3

2,000

1

700

1

700

4

250

AO 43 Tappahannock

16,000

16.5

70,000

16,000

14,800

100,800

3

2,000

1

700

1

700

4

250

AO 44 Patuxent

16,000

16.5

70,000

16,000

14,800

100,800

3

2,000

1

700

1

700

4

250

AO 46 Victoria

10,840

10.5

65,000

0

0

65,000

2

2,000

AO 47 Neches

16,000

16.5

74,000

15,467

14,270

103,737

3

2,000

1

700

1

700

4

250

AO 48 Neosho

15,510

16.5

71,000

15,000

14,000

100,000

3

2,000

1

700

1

700

4

250

AO 49 Suamico

16,000

14.5

75,000

16,000

15,000

106,000

3

2,000

1

400

1

700

4

250

AO 50 Tallulah

16,000

14.5

75,000

16,000

14,000

105,000

3

2,000

2

400

1

700

4

250

AO 51 Ashtabula

18,250

18 0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

700

4

250

AO 52 Cacapon

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 53 Caliente

18,250

18.0

79,800

16,500

18,600

114,900

3

2,000

2

1,400

1

1,400

4

250

AO 54 Chikaskia

18,250

18.0

79,800

16,500

18,600

114,900

3

2,000

2

1,400

1

1,400

4

250

AO 55 Elokomin

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 56 Aucilla

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 57 Marias

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 58 Manatee

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 60 Nantahala

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 61 Severn

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 62 Taluga

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 63 Chipola

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 64 Tolovana

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 65 Pecos

16,000

14.5

79,000

15,800

13,700

108,500

3

2,000

2

400

1

700

4

250

AO 66 Atascosa

18,450

16.0

83,200

16,300

12,500

112,000

2

2,800

1

700

1

700

4

250

AO 67 Cache

16,560

14.5

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 68 Chiwawa

16,400

15.5

76,000

16,000

17,850

109,850

2

2,800

1

700

1

700

4

250

AO 69 Enoree

16,400

15.5

76,000

16,000

17,850

109,850

2

2,800

1

700

1

700

4

250

AO 70 Escalante

16,616

15.5

76,000

16,000

17,850

109,850

2

2,800

1

700

1

700

4

250

AO 71 Neshanic

16,400

14.5

74,100

16,000

18,300

108,400

2

2,800

1

700

1

700

4

250

AO 72 Niobrara

16,400

15.5

76,000

16,000

17,850

109,850

2

2,800

1

700

1

700

4

250

AO 73 Millicoma

16,560

14.5

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 74 Saranac

16,560

14 5

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 75 Saugatuck

16,560

14.5

87,300

14,300

13,500

115,100

3

2,000

2

400

1

700

4

250

AO 76 Schuylkill

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 77 Cossatot

16,560

14.5

75,000

16,000

15,000

106,000

3

2,000

2

400

1

700

4

250

AO 78 Chepachet

16,560

14.5

75,000

16,000

15,000

106,000

3

2,000

2

400

1

700

4

250

AO 79 Cowanesque

16,560

14 5

75,000

16,000

16,000

107,000

3

2,000

2

400

1

700

4

250

AO 80 Escambia

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 81 Kennebago

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 82 Cahaba

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 83 Mascoma

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 84 Ocklawaha

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 85 Pamanset

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 86 Ponaganset

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 87 Sebec

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 88 Tomahawk

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 93 Soubarissen†

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 94 Anacostia

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 95 Caney

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 96 Tamalpais

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 97 Allagash

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 98 Caloosahatchee

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 99 Canisteo

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 100 Chukawan

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 101 Cohocton

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 102 Concho

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 103 Conecuh

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 104 Contoocook

16,560

16.0

77,400

15,600

14,000

107,000

3

2,000

2

400

1

700

4

250

AO 105 Mispillion

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 106 Navasota

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 107 Passumpsic

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

AO 108 Pawcatuck

18,250

18.0

79,800

16,500

18,000

114 300

3

2,000

2

1,400

1

1,400

4

250

AO 109 Waccamaw

18,250

18.0

79,800

16,500

18,000

114,300

3

2,000

2

1,400

1

1,400

4

250

* The fuel capacities shown are segregated as to products for which tanks were allocated in design. Capacities will vary when these tanks are utilized for other products. A rough conversion to total fuel capacity may be made by reducing Diesel capacity by 12 percent and gasoline capacity by 24 percent.